This disclosure relates generally to a feeder apparatus utilized in electronic reprographic printing system, and more particularly concerns a feeder apparatus for feeding of tab stock.
In the process of electrostatographic reproduction, a light image of an original to be copied or printed is typically recorded in the form of a latent electrostatic image upon a photosensitive member, with a subsequent rendering of the latent image visible by the application of electroscopic marking particles, commonly referred to as toner. The visual toner image can be either fixed directly upon the photosensitive member or transferred from the member to another support medium, such as a sheet of plain paper. To render this toner image permanent, the image must be “fixed” or “fused” to the paper, generally by the application of heat and pressure.
Sheet handling systems feed paper or other media through each process station in a rapid succession in a reliable and dependable manner in order to utilize the full capabilities of the reproduction machine. These sheet handling systems must operate flawlessly to virtually eliminate risk of damaging the recording sheets and generate minimum machine shutdowns due to mis-feeds or multi-feeds. It is in the initial separation of the individual sheets from the media stack where the greatest number of problems occurs.
Some sheet feeding apparatus (commonly referred to as “fluffers” or “air knives”) utilize positive air flow over the top sheet in a stack of sheets and air flow between sheets at the leading edge to separate the top sheet from underlying sheets so that only the top sheet is captured for feeding. The use of fluffers or air knives to help separate and/or levitate sheets for improved sheet separation and feeding is an extensively developed art, with numerous patents. The following are noted by way of some recent examples of U.S. patents with disclosures of such systems, and for other such art cited therein: U.S. Pat. No. 6,186,492 issued Feb. 13, 2001 to Dechau, et al; U.S. Pat. No. 6,264,188 issued Jul. 24, 2001 to Taylor, et al; and U.S. Pat. No. 6,352,255 issued Mar. 5, 2002 to Taylor and U.S. Pat. No. 6,746,011 issued Jun. 8, 2004 to Miller et al. U.S. Pat. No. 6,186,492 also discloses an example of a reciprocating vacuum feed head or “shuttle feeder,” with which the disclosed tab guide may be desirably combined, but is not limited thereto.
Sheet fluffers may also be combined in the same sheet separator/feeder system with what may be alternatively called “air knives” blowing against at least the upper portion of the front, feeding out, or downstream edge or a side edge of the stack in coordination with the individual sheet acquisition and feeding. Stack fluffing and/or vacuum sheet feeding is particularly desirable for higher speed printing systems, for providing more reliable high speed sheet separation and feeding and also for reduced marking or scuffing of sheet surfaces as compared to “friction retard” or other such sheet separator/feeders which are more commonly used on slower, lower cost, printers.
As used herein, the term “printers” will be understood to broadly include copiers, printers, multifunction devices, etc., with xerographic, ink jet, or other print media printing systems. The term “sheet” as used herein refers to various print media sheets, of various sizes and weights, typically relatively thin, flexible or even flimsy paper, and sometimes even plastic (such as for overhead transparencies). As used herein, the term “tab stock” will refer to sheets having an even edge and an opposed uneven edge with a projection spaced along such uneven edge. The projection (tab), which for example can serve as a location for a label (pre-printed or printed by the reproduction apparatus), enables the sheet to separate or provide divisions in a copy set.
Fluffer feeders typically utilize paper trays for supporting the stacks of sheets that include side guides and edge guides for maintaining the sheets in proper orientation and position for feeding. Trail edge guides often include actuator arms or stack height fingers for engaging the top surface of the top sheet in the stack adjacent the “trailing edge” (i.e. the edge opposite the “leading edge” which is the first edge of the sheet to entire the transfer device). It will also be appreciated that various types of variously slide-mounted or otherwise movable stack side and edge guides are well known in the art, for various sheet stacking trays, and thus all such side and edge guides need not be described in any detail herein. Such side and edge guides can be reset to the size of the stack of sheets currently being loaded into the tray to generally confine the sheets between such guides.
The stack side guides can also assist in linear sheet feeding of the sheets in the orthogonal feeding direction. One, or both, opposing side guides (herein referred to as front and rear side guides because of the feed direction of the sheets) may be movable. If both side guides are moveable they may optionally be ganged for coordinated movement towards or away from one another by a rack and pinion connection, as is also well known, e.g. U.S. Pat. Nos. 5,511,771 and 5,946,527. This allows for a “center registered” sheet feeding system instead of an “edge registered” system. An “edge registered” system is shown in U.S. Pat. No. 6,302,390. In a “center registered” sheet feeding system, such as that illustrated herein, in which the side guides are ganged the operator resetting movement of one side guide automatically moves the opposing side guide.
A movable stack trail edge guide is also provided in sheet feeding trays, opposite from the feed-out end of the stack, movable in the process direction. The trail edge guide may also be movable at an angle to the stack for substantially centering on the trailing edge of different widths of sheet stacks, as in Xerox Corp. U.S. Pat. No. 6,302,390.
In many paper trays, the trail edge guides are configured to engage only a central portion of the edges of the stacks of sheets that they position and orient. Thus, substantial portions of the trailing edges of the sheets in the stack are not in engagement with the trail edge guide. Also, the actuator arm or stack height finger is typically disposed within the trail edge guide. The actuator arm or stack height finger engages a portion of the center of the top surface of the top sheet in the stack adjacent the trailing edge. The actuator arm or stack height finger acts as a sensor to control the sheet elevator in the paper tray to properly position the top sheet of the stack for acquisition by the feeder head. The actuator arm or stack height finger also applies a very light (to avoid marking the sheet) downward force on the top sheet of the stack which facilitates the use of a fluffer.
Such trail edge guides and actuator arms operate very well with sheets having even trailing edges. However, such guides and actuator arms may not operate well when tab stock is loaded in the tray with the uneven edge (the edge including the tabs) being positioned as the trailing edge.
Due at least in part to the projections, typical reproduction apparatus sheet feeders have some difficulty in reliably feeding tab stock. Tab stock is typically oriented in printers so that the uneven edge is the trailing edge to avoid feeding, transfer and registration problems that may arise when transferring tab stock with the uneven edge being the leading edge. Such problems are well documented and need not be explained in any detail.
The individual tabbed sheets of the tab stock sheet stack, as best seen in FIG. 4, respectively have tabs (in the illustrated embodiment including five tab stock referred to as T1-T5) spaced along an uneven marginal edge of the stack. The uneven marginal edge can be envisioned as having an even marginal edge portion or portions in the areas where the tab is not located and a tabbed marginal edge projecting beyond the even marginal edge portion. As such, although the even marginal edge portion of the stack itself is even, the tabbed marginal edge of each sheet is not even. It is common for the tabbed marginal edge to project between nine to thirteen millimeters beyond the even marginal edge portion of the uneven edge of tab stock.
The tabs are located longitudinally in different locations along the uneven edge of the tab stock. Alphabetical tab stock in English speaking countries often comes in sets that include twenty-six differently lettered tabs. Each differently lettered tab is in a different position along the uneven edge of the tab stock. The width of the each tab in a tab stock set is often approximately equal to the length of the uneven edge divided by the number of differently positioned tabs in the set. Numbered and blank tab stock sets may include more or fewer differently positioned tabs along the uneven edge. It is common for tab stock sets to include as many as thirty-one differently positioned tabs. Thus, only the tabs on tab stock having the tab positioned in the center region of the uneven edge of a tab stock set would engage a trail edge guide that is designed to engage the center of the sheets in the paper tray. Other tab stock in the tab stock set would not be restrained in the proper orientation by such a trail edge guide. As an example, portions or all of tabs T2, T3, and T4 would be in engagement with the illustrated trail edge guide while tabs T1 and T5 would not engage the illustrated trail edge guide.
Actuator arms or stack height fingers that are disposed in trail edge guides are typically relatively thin so that they engage only a small portion of the top surface of the top sheet in the stack. The actuator arms or stack height fingers typically do not extend too far (around six to fifteen millimeters) in the process direction away from the trail edge guide. Thus, when a tab stock set is loaded in a paper tray with the uneven edge oriented as the trailing edge, some shorter stack height fingers would engage only the tabs on the tab stock in the tab stock set that have the tabs positioned in the center of the uneven edge while longer stack height fingers would engage the top surface of all of the tab stock very close to the trailing edge. When tab stock in the tab stock set that does not have its tab positioned in the center of the uneven edge becomes the top sheet in the stack, the stack height finger either does not engage the tab stock or engages only a very small portion of the top sheet in the stack adjacent the even marginal edge portion of uneven trailing edge.
The stack height finger disclosed herein extends approximately fourteen millimeters in the process direction away from the trail edge guide. Thus, when used with typical tab stock, the disclosed stack height finger would only extend between one to five millimeters beyond the even portion of the uneven marginal edge to engage the top surface of tab stock having non-centered tabs. This can adversely affect the operation of the fluffer which when blowing may cause the stack height finger to become disengaged from the top sheet of the stack and result in inaccurate positioning of the top sheet relative to the feeder head.
Owners and operators of printers would appreciate a device that properly positions and orients tab stock for feeding. A device that properly engages the top surface of the top sheet in a stack adjacent the trailing edge of tab stock to facilitate fluffer feeding of the tab stock would also be appreciated. A device that could be added to a current paper tray to facilitate handling of tab stock without modification or replacement of the tray would also be appreciated.
According to one aspect of the disclosure, a tab guide is provided for aligning tab stock in a paper tray of a printer having a trail edge guide including a substantially planar sheet-engaging face and a stack height finger extending from the sheet-engaging face in a process direction for engaging a top surface of a top sheet on a stack adjacent the trailing edge of the sheet. The tab guide comprises a top flange, a trailing edge flange and a mount. The top flange has a top surface and a sheet-engaging surface. The trailing edge flange has a substantially planar trailing edge-engaging surface. The mount couples the top flange and the trailing edge flange. The mount is configured to removably mount the top flange and trailing edge flange to the trail edge guide and when so mounted to position the top surface of the top flange in engagement with a bottom of the stack height finger, to position the sheet-engaging surface of the top flange in engagement with the top surface of the top sheet in a stack of tab stock received in the paper tray and to position the trailing edge-engaging surface of the trailing edge flange in engagement with tabs located on the trailing edge of a plurality of the uppermost sheets in the stack of tab stock received in the paper tray.
According to another aspect of the disclosure, a method of configuring a paper tray having a trail edge guide with a substantially planar sheet-engaging face having a width and a stack height finger to properly align tab stock is provided. The stack height finger has a width and extends a length in a process direction from the sheet-engaging surface. The tab stock has a length along an uneven edge and includes tabs extending a width from an even marginal edge thereof. The tab stock is positioned adjacent the trail edge guide. The method comprises temporarily effectively extending the width of the sheet-engaging face to approximately equal to or less than the length of the uneven edge and temporarily effectively extending the length of the actuator arm to significantly greater than the width of the tab.
According to yet another aspect of the disclosure, a paper tray for an electrostatographic printer for properly aligning tab stock having an uneven edge including tabs to be processed with the uneven edge being the trailing edge of the tab stock is disclosed. The paper tray comprises a sheet-receiving region, a trail edge guide and a tab guide. The sheet-receiving region receives a stack of sheets to be fed to the electrostatographic printer in a feed direction and has a lead edge side and a trailing edge side having a length. The trail edge guide is adjacent the trailing edge side of the sheet-receiving region and movable into engagement with a trailing edge of a stack of sheets received in the sheet-receiving region. The trail edge guide includes a sheet-engaging face having a width less than the length of the trailing edge side of the sheet-receiving region. The tab guide includes a top flange, a trailing edge flange and a mount. The top flange has a top surface and a sheet-engaging surface. The trailing edge flange has a substantially planar trailing edge-engaging surface. The mount couples the top flange and the trailing edge flange. The mount is configured to removably mount the top flange and trailing edge flange to the trail edge guide and when so mounted to position the top surface of the top flange in engagement with a bottom of the stack height finger, to position the sheet-engaging surface of the top flange in engagement with a top surface adjacent a trailing edge of a top sheet in a stack of tab stock received in the sheet-receiving region and to position the trailing edge-engaging surface of the trailing edge flange in engagement with tabs located on a trailing edge of a plurality of the uppermost sheets in the stack of tab stock received in the sheet-receiving region.
Additional features and advantages of the presently disclosed tab guide will become apparent to those skilled in the art upon consideration of the following detailed description of embodiments exemplifying the best mode of carrying out the disclosure as presently perceived.
Corresponding reference characters indicate corresponding parts throughout the several views. Like reference characters tend to indicate like parts throughout the several views.